Photocurrent generation of a single-gate graphene p-n junction fabricated by interfacial modification

Area of Science:

• Materials Science
• Nanotechnology
• Condensed Matter Physics

Background:

• Graphene field-effect transistors (FETs) are promising for electronic applications.
• Achieving stable and efficient graphene p-n junctions is crucial for optoelectronic devices.
• Interfacial modification techniques are key to controlling graphene's electronic properties.

Purpose of the Study:

• To fabricate a back-gate graphene p-n junction using selective interfacial modification.
• To investigate the photocurrent response of the fabricated graphene p-n junction.
• To demonstrate the potential of this method for creating efficient graphene-based photodetectors.

Main Methods:

• Utilized chemical vapor deposition (CVD)-grown graphene FETs.
• Fabricated p- and n-doped regions using silane self-assembled monolayer (SAM) patterns.
• Analyzed gate-dependent photocurrent and spatial photocurrent mapping.

Main Results:

• A sharp graphene p-n junction was successfully formed via SAM patterning.
• Observed a gate-dependent photocurrent response with a maximum signal between Dirac points.
• Demonstrated significantly higher photocurrent at the junction compared to graphene/electrode interfaces.
• Identified photothermoelectric contribution as the dominant factor in photocurrent generation.

Conclusions:

• Selective SAM interfacial modification is a feasible route for fabricating graphene p-n junctions.
• The developed method enables efficient photocurrent generation, suitable for photodetector applications.
• This approach offers a pathway for advanced graphene-based optoelectronic devices.